Device for replacing fuse wire and for indicating blown-out electric circuits



July 3, 1923.

F. DAVIES DEVICE FOR REPLACING FUSE'WIRE AND FOR INDICATING BLOWN'OUTELECTRIC CIRCUITS Filed Dec. 9, 19193 5 Sheets-$heet 1 July 3, 1923.1,460,478 P. DAVIES DEVICE FOR REPLACING FUSE WIRE AND FOR INDICATINGBLOWN-OUT ELECTRIC CIRCUITS Filed Dec 9 1919 3 Sheets-Sheet 2 P. DAVEESND FOR INDICATINGv BLOWN-OUT ELECTRIC CIRCUITS July 3, 1923.

DEVICE FOR REPLACING FUSE WIRE A 5 SheetsSheet 3 Filed Qec.

1 .17 a/v L365,

Patented July 3, 1923.

UNITED STATES PATENT OFFICE.

PHIL DAVIES, OF WOOLLAI-IRA, SOUTH WALES, AUSTRALIA.

DEVICE FOR REPLACING FUSE WIRE AND FOR INDICA'IING BLOWN-OUT ELECTRICCIRCUITS.

Application filed December 9, 1919.

T all whom it may concern:

Be it known that I, PHIL DAVIES, subject of the King of Great Britainand Ireland, residing at 112 Oxford Street, lVoollahra, in

the State of New South Wales, Commonwealth of Australia, have inventednew and useful Improvements in a Device for Replacing Fuse lVire and forIndicating Blown-Out Electric Circuits, of which the following is aspecification.

The object of this invention is to provide a fuse replacing appliancewhich is efficient and. so simple to operate that any ordinary unskilledperson may install a new fuse by merely turning a handle. The mainfeatures are that (1) it is practically impossible to insert a fuse wireto carry a heavier current than that for which the appliance is intended(2) should the fuse blow the fact is immediately revealed by anindicator on the face of the appliance (3) a fresh supply of fuse wiremay be quickly inserted, the spool being so constructed that it isimpossible to insert it in the appliance in any but the right Way and(4) only a spool box especially constructed for this appliance can beused.

The appliance consists of a box, of suitable size, shape and material,in which is a rotatable block and a spool box, the latter having twoprojecting curved arms, one on either side, the extremities of thesecurved arms being turned over in such a way as to form channels in whichthe free end of the fuse Wire may be loosely held in position ready forthe appliance to be operated. The rotatable block is approximately ovalin shape the underside having a centrally situated circular boss that isseated within a washer-like member formed in the bottom of the box. Aportion of the wall of this washer-like member forms a ratchet whichpermits the block to be rotated in one direction only, the next sectionbeing plain, while another, smaller, portion of the wall is cut away toform an indentation to accommodate the foot of a transversespring-operated stop which is forced out by the action of the springwhen it is released by the fuse wire blowing. Partially surrounding thewasherlike member and of larger internal diameter, is a narrow platformor second washer-like member, one portion of which is provided SerialNo. 343,588.

with an incline leading from the upper surface of the first washer-likemember to the upper surface of the second washer-like member orplatform, while another portion of the second washer-like member isprovided with an incline leading down from the upper surface of theplatform to the up per surface of the first washer-like member.Diametrically opposite disposed pole pieces extend through bothwasher-like members. These pole pieces are secured in the base of thebox, the electrical connection being made on the underside of the baseof the box, the upper ends of the pole pieces lying flush with thesurface of the platform or second washer-like member.

The rotatable block revolves upon a spindle rigidly secured to the baseof the box, and consists of two main parts, viz :an upper and lowerpart. Near each end of the block is a plunger operated by a spring whichcauses the plunger to make a continuous rubbing contact along a portionof the platform and a portion of the first washerlike member and forcesthe plunger out of action when it passes the second pole piece and atthat point releases the loose piece of wire which has been fused andwhich will drop out through an opening provided for the purpose in thewall of the box At each end of the rotatable block is a slot formed bycutting away a portion of the underside of the upper part of the block.The gripping end of the plunger lies normally flush with the upper faceof the lower part of the block. The plunger will be forced into one ofthe slots as it passes up the incline on to the platform.

It will be assumed that the appliance is ready for use and that it isdesired to insert a fuse in the electrical circuit. The handle is givena half turn in the direction of the hands of a watch. As the block isrotated one of the plungers will come into contact with the inclineleading up to the upper surface of the platform. The fuse wire that isstretched from one arm of the spool box to the other has now entered theslot in the end of the block and is lying immediately over the end ofthe plunger, so that as the blocl is rotated the plunger is gradw allyraised by the incline and being forced up into the recess in the upperpart, carries with it and firmly grips the fuse wire that is stretchedfrom one arm of the spool box to the other arm, pulling the free end outof the channel in one arm on the spool box and drawing it through thechannel on the other arm from the spool within the spool box. As all theparts have not yet been brought into operation the handle will in thiscase fl back taking with it the pointer to the off position. The handleis then given a second half turn and the block be ing thereby rotatedwill first bring the foot of a transverse spring-operated stop, againstthe plain portion of the wall of the race forcing it in and holding ituntil the wire is gripped by the second plunger. The foot of the stop isthen opposite the indentation in the inner edge of the first washer-likemember but is prevented from entering that indentation by the fuse wirewhich is gripped tightly by the plungers at the opposite ends of theblock. In this position the tail of the transverse stop is projectingbeyond the other side of the block and abuts against a stud projectingupwardly from the base of the appliance close to the inner edge of thefirst washer-like member, thus forming an independent stop to therotation of the block. The plungers are now immediately over and invertical contact with the two poles in the platform or secondwasher-like member, the two being in electrical connection through thefuse wire that is gripped by them. The foot of a second transverse stop,situated on the other side of the minor axis of the block, is now inengagement with the ratchet in the wall of the race, thus preventing theblock from being rotated in a backward direction. Leaving the appliancein this position and passing to the means for operating it, a handleprovided with a pointer is mounted upon a spindle, upon which therotatable block revolves, and secured by means of a screw. The handle isprovided with a short hollow boss which passes through an opening in thelower half of the lid of the box. This opening is made by cutting twoconcentric semi-circles so that the movement of the handle may belimited to a half turn by means of a stud projecting from the un derside of the pointer. The inner end of the hollow boss is made square,the square portion engaging with a rectangular lever plate havingshallow walls. This lever plate revolves upon the block spindle, thehole through which the spindle passes being close to one end of theplate. The sides at the other end of the plate are adapted to engagewith stops as hereafter described. Surrounding the spindle, between theunderside of the handle and the lever plate, is a coil spring adapted torotate the lever plate and handle backward when the plate is released bythe. transverse stop that is forced out by the action of the spring whenthe fuse wire blows, the foot of the stop entering the indentation inthe inner edge of the first washer-like member.

On each side of the minor axis of the rotatable block and diagonallyopposite one another are two rigid stops having inclined leads to theirfaces. When the appliance is set, the long end of the rectangular leverplate is seated between the right stop and the upper end of thetransverse spring-operated stop. It is then impossible to turn thehandle in either direction because the stud on the underside of theindicator hand prevents it from being turned forward while the fuse wiregripped between the plungers is holding one of the transversespring-operated stops in the forced back position, the head of such stopbeing in engagement with the rectangular lever plate, the foot of theother transverse stop being in engagement with the ratchet in the firstwasher-like member at the bottom of the box thus preventing an backwardmovement. When an overloac occurs and the fuse blows, the transversestop that was held by the fuse wire is released, its spring forcing itoutwards into the recess in the first washerlike member, the rectangularlever plate, being operated by its spring is rotated backward carryingwith it the operating handle and indicator hand, is forced up and overthe inclined lead on the rigid stop, drops down and is held inengagement with the upper end of the other transverse stop. The foot ofthis transverse stop 'is then in engagement with the ratchet in therace. In this position the indicator hand is pointing upward showingthat the fuse has blown and is ready for a new fuse to be placed incircuit by giving the handle a half turn.

In order that the invention may be more clearly understood referencewill now be made to the accompanying sheet of drawings in which Fig. 1is a perspective view of the fuse replacing appliance showing theindicator hand in the unset position.

Fig. 2 is a similar view of the appliance showing the indicator hand atthe unset position, certain parts being broken away to illustrateportions of the internal mechanism.

Fig. 3 is a front view of the appliance with the cover removed and apart shown in section.

Fig. 4 is a central vertical sectional view of the appliance withcertain parts shown in side elevation.

Fig. 5 is a front view of the block and wire spool, illustrating themanner in which the wire carried by the spool is gripped by the block.

F ig. 6 is a detail sectional view illustrating the manner in-which oneof the adjust able stops functions to hold the block in adjustedpositions.

Fig. 7 is a perspective view of the appliance with the front cover, theinternal block and other parts removed.

Fig. 8 is a perspective view of the cover.

Fig. 9 is a perspective view of the inner or lower portion of the block.

Fig. 10 is a similar view of the upper portion of the block.

Fig. 11 is a view similar to F i 9 but showing the adjustable stops andthe block supporting spindle removed from the block.

Fig. 12 is a perspective view of the adjustable stops.

Fig. 13 is a perspective view of the operating handle, indicatorpointer, handle operated lever and the spring of the handle operatedlever. p

Fig. 14 is a perspective view of the special form of spool employed inthe improved apparatus.

Fig. 15 is a. perspective view of the casing partly broken away to showthe washerlike members.

Fig. 16 is a central vertical sectional view of the appliance.

Fig. 17 is a detail sectional view illustrating one of the fuse wireengaging plungers.

1 is the box, 2 the upper half of the cover thereof which is secured inposition by a milled nut 3, the handle 5 being kept in position by thescrew 6. The lower half of the cover 4 will be provided with lugs 7 bywhich to secure it to the box by means of screws 8. Two concentricsemi-circular apertures 9 and 10 are cut in the lower half of the cover,the point of junction between the two semi-circles forming shoulders 11thus forming a stop; to limit the movement of the handle. The handle isprovided with a pointer 12, on the inner side of which is a pin 13 thatengages with the shoulder stop 11 thus limiting the movement of thehandle to a half turn. At the rear of the handle and integral therewithis a hollow boss 14 the extreme end 15 of which is made square.

Upon the base within the box is a washerlike member 16 the inner edge ofwhich is divided into three sections the ratchet 17 plain section 18 andindentation 19. Partially surrounding and upon the wall of the member 16is a second washer-like member 20 having an outside diameter equal tothat of the member 16 but whose inside diameter is larger than theinside diameter of said member 16. The upper end of the inner edge ofthe member 20 is inclined to form an incline 21 leading from the uppersurface of the member16 to the upper surface of the member 20. A similarincline 21 leads from the upper surface of the member 20 down to theupper face of the member 16. The member 20, as shown in Fig. 16, isconnected to the pole pieces 22 by means of which the appliance isplaced in the electric circuit in a manner well known and understood.The inner ends of the pole pieces 22 are flush with the outer surface ofthe platform 20.

A rotatable block 23, formed of inner and outer sections 25, 24 and acircular boss 26, is arranged within the casing 1, and the boss 26 isseated within the members 16 and 20 and these sections and the boss areaxially secured in position by the spindle 27 upon which they and thehandle 5 rotate. In the inner part 25 of the block 23 are two parallelslots, one on either side of the spindle, in which are transverse steps28 operated by springs 29 and each provided with a head 30 adapted toengage with a lever plate 31. Each of the stops also has a long leg 32,which engages with the different sections of the inner edge of themember 16, and a short leg or tail piece 33, the function of which is toengage with the stop 34 projecting from the upper portion of the member16. The springs 29 are held in compression between shoulders 35, in thetransverse stops 28, and cross pieces 36 let into the upper surface ofthe inner part 25 of the rotatable block. Near the ends of the section25 are recesses 37 in which are secured, in any suitable and convenientmanner, plungers 38 provided with sleeves 38 composed of a suitableinsulating material, and collars 39, such plungers being operated bysprings 40. The underside of the outer section 24 of the rotatable blockis cut away to a. certain depth at each end so as to form recesses 4Othrough which the fuse wire 42 will pass to be held by the plungers 38as the latter are forced out by passing up the incline 21 on to themember 20. lVhile the lower end of the plunger is travelling over themember 20 it continues to grip the fuse wire but immediately it passesover the incline 21 in which the platform terminates, it is free to beforced out by the spring 40 thus releasing the short piece of wireremaining after the fusing has taken place, and this short piece of wirewill drop out through the cut away portion 43 in the wall of the box.

The upper part 24 of the rotatable block is provided with slots 24 oneither side of the axis, and diagonally opposite one another. The heads30 of the transverse stops 28 project into and above these slots, itbeing the projecting heads that engage with the rectangular lever plate31. On the upper surface of the part 24 of the block 23 are two stops 44having inclined leads to their faces. One of these stops 44 is oppositeto the heads 30 of each of the transverse stops 28. Referringto Fig. 3of the drawings the appliance is shown set, the fuse having been placedin the electric circuit. When an overload takes place the wire will fuseat some point between the two plungers by which it glt is gripped thusreleasing the head of the stop 28 which is forced outwardly by thespring 29, the foot 32 enters the indentation 19 at the same timedrawing with it the short leg or tail piece 33 which is thereby freedfrom the stop 34; the head 30 having been forced out by the spring 29,releases the lever plat 31 which is rotated in an anti-clockwisedirection by the action of the helical spring on the spindle 27 and inits travel backwards the long end of the lever plate 31 passes up andover the inclined surface of the stop 44 until it abuts against the head30 of the other transverse stop, in which position it will be forceddown between the two stops by the helical spring 45 and the appliance isthen ready for a new fuse to be placed in the circuit. This is done bygiving the handle 5 a half turn as hereinbefore described, th leverplate being then in engagement with the face 46 of the'stop 44 therotation of the handle, and with it the lever plate, will cause theblock 23 to rotate with them in a clockwise direction.

The spool box 47, in which is the spool 48, is secured upon a pin 49 andis provided with curved arms 50, the outer peripheries of which areadapted to lie close to the inner wall of the box 1 in order to preventthe spool box and arms from moving in order that only a spool boxspecially constructed for this appliance and which will carry thecorrect fuse wire may be inserted in the appliance, the outer peripheryof one of the arms 50 is provided with a recess 53 which engages aprojecting tooth 54 integral with the wall of the appliance. Upon thespool 48 is wound a suitable supply of fuse wire 42 the free end ofwhich passes out through an opening in the side of the box, through thechannel formed by the turned over portion 51 of the, arm 50 and fromthence to the channel formed by the turned up portion 52 of the otherarm 50 by which it is lightly gripped ready for the appliance to bebrought into operation The spool box 47 is-intended to be a metalstamping and will be closed or sealed after the wire spool has beeninserted in the box. It will be noted from the drawings that the spoolbox is integral with the arms 50, and it would therefore be necessary todestroy the box in order to place fresh wire upon the spool. All spoolscarrying fuse wire of a given gauge will be provided with arms havingthe recess 53 placed in proper position for operation with the member54, and this latter member will always be in the same position on allappliances intended to carry up to a given load. Consequently the spoolbox may only be replaced by a similar spool box carrying a wire of thesame gauge.

I claim:

1. In a device for replacing fuse wire and for indicating blown outelectric circuits,

a. spool and spool box adapted to carryacoil of fuse wire, two curvedarms integral with the spool box, one of said arms being provided with arecess, a corresponding tooth to [it into the recess, and means on thearms through which the fuse wire may be threaded and held stretched fromone arm to the other for the purpose herein described.

2. In a device for replacing fuse wire and for indicating blown outelectric circuits such as is herein described an indicator hand or.pointer integral with a handle for operating the appliance and a springofpe'ated lever plate for the purpose spec- 1 e 3. In a device forreplacing fuse wire and for indicating blown out electric circuits, anindicator hand or pointer integral with a handle for operating theappliance and means for automatically returning the handle to theoperative position for the purposes specified.

4. In a device for replacing fuse wire and for indicating blown outelectric circuits, an approximately oval shaped two piece rotatableblock, stops on the rotatable block adapted to engage with a leverplate, the ends of the rotatable block being provided with slots throughwhich the fuse wire may pass, transverse cam-operated plungers that gripthe wire within the slots as the block is rotated, such plungers havingsleeves of suitable insulating material and being adapted to makecontact with the pole pieces in an electric circuit for the purposesspecified.

5. In a device for replacing fuse wire, a wire holding spool and meansfor supporting a portion of the wire which has been withdrawn from thespool, a member automatically actuated in one direction and manuallyactuated in the opposite direction and provided with means for engagingthe wire, and means for disengaging the last named means from the wirewhen said member is actuated.

6. In a device for replacing fuse wire, a spool support, a sealed spoolbox engageable with said support and carrying a spool of fuse wire, andcooperating means provided on the support and spool box to permit thespool to be placed on the support. one of said means functioning toprevent spool boxes other than a uniform type from being placed on thesupport.

7. A device for replacing fuse wire comprising a wire holding spool andmeans for supporting a portion of thewire which has been withdrawn fromthe spool, a rotatable block provided with a plurality of grippingmembers designed to engage and grip the wire, means for forcing saidgripping members out of operative position to permit the same to releasethe wire, means actuated during rotation of the block for causing thegripping members to grip the wire automatically operated means formoving the block in one direction, and manually actuated means formoving the block in an opposite direction.

8. A device for use in replacing fuse wire and for indicating blown outelectric circuits comprising a casing provided with superposed inner andouter washer-like members, the inner member having its inner edge shapedto provide a segmental ratchet, a curved portion and an indentation, afuse wire support located in the easing, a block rotatably mounted inthe casing and provided with grippers for the fuse wire, spring actuatedstops carried by the block and each designed to engage the fuse wire ata point between the grippers, said stops cooperating with the ratchetsegment to prevent the block from rotating in one direction only, theindentation being adapted to permit movement of each stop under theinfluence of its spring when said stop isreleased by the breaking of thewire between the grippers, and means for rotating the block to bringsuccessive stops into engagement with the fuse wire.

9. A device of the kind defined by claim 8 in which the outerwasher-like member is provided with inclined surfaces designed to engagethe grippers to force the same into engagement with the wire and springsfor releasing the grippers from the wire.

10. A device of the kind defined by claim 8 in which the outerwasher-like member is provided with oppositely disposed inclinedsurfaces which lead from the outer surface of the inner washer-likemember to the outer surface of the outer washer-like member, and springsengaging said grippers and normally pressing on the same to cause thegrip pers to release the wire, said grippers cooperating with thewasher-like members and the inclined surfaces to grip the wire when thegrippers engage one of said inclined surfaces.

In testimony whereof I have signed my name to this specification.

PHIL DAVIES.

